[patch 6/7] drm/i915: Replace io_mapping_map_atomic_wc()

[Thomas Gleixner]

From: Thomas Gleixner <tglx at linutronix.de>

None of these mapping requires the side effect of disabling pagefaults and
preemption.

Use io_mapping_map_local_wc() instead, and clean up gtt_user_read() and
gtt_user_write() to use a plain copy_from_user() as the local maps are not
disabling pagefaults.

Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: intel-gfx at lists.freedesktop.org
Cc: dri-devel at lists.freedesktop.org
---
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c |    7 +---
 drivers/gpu/drm/i915/i915_gem.c                |   40 ++++++++-----------------
 drivers/gpu/drm/i915/selftests/i915_gem.c      |    4 +-
 drivers/gpu/drm/i915/selftests/i915_gem_gtt.c  |    8 ++---
 4 files changed, 22 insertions(+), 37 deletions(-)

--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -1080,7 +1080,7 @@ static void reloc_cache_reset(struct rel
 		struct i915_ggtt *ggtt = cache_to_ggtt(cache);
 
 		intel_gt_flush_ggtt_writes(ggtt->vm.gt);
-		io_mapping_unmap_atomic((void __iomem *)vaddr);
+		io_mapping_unmap_local((void __iomem *)vaddr);
 
 		if (drm_mm_node_allocated(&cache->node)) {
 			ggtt->vm.clear_range(&ggtt->vm,
@@ -1146,7 +1146,7 @@ static void *reloc_iomap(struct drm_i915
 
 	if (cache->vaddr) {
 		intel_gt_flush_ggtt_writes(ggtt->vm.gt);
-		io_mapping_unmap_atomic((void __force __iomem *) unmask_page(cache->vaddr));
+		io_mapping_unmap_local((void __force __iomem *) unmask_page(cache->vaddr));
 	} else {
 		struct i915_vma *vma;
 		int err;
@@ -1194,8 +1194,7 @@ static void *reloc_iomap(struct drm_i915
 		offset += page << PAGE_SHIFT;
 	}
 
-	vaddr = (void __force *)io_mapping_map_atomic_wc(&ggtt->iomap,
-							 offset);
+	vaddr = (void __force *)io_mapping_map_local_wc(&ggtt->iomap, offset);
 	cache->page = page;
 	cache->vaddr = (unsigned long)vaddr;
 
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -253,22 +253,15 @@ gtt_user_read(struct io_mapping *mapping
 	      char __user *user_data, int length)
 {
 	void __iomem *vaddr;
-	unsigned long unwritten;
+	bool fail = false;
 
 	/* We can use the cpu mem copy function because this is X86. */
-	vaddr = io_mapping_map_atomic_wc(mapping, base);
-	unwritten = __copy_to_user_inatomic(user_data,
-					    (void __force *)vaddr + offset,
-					    length);
-	io_mapping_unmap_atomic(vaddr);
-	if (unwritten) {
-		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
-		unwritten = copy_to_user(user_data,
-					 (void __force *)vaddr + offset,
-					 length);
-		io_mapping_unmap(vaddr);
-	}
-	return unwritten;
+	vaddr = io_mapping_map_local_wc(mapping, base);
+	if (copy_to_user(user_data, (void __force *)vaddr + offset, length))
+		fail = true;
+	io_mapping_unmap_local(vaddr);
+
+	return fail;
 }
 
 static int
@@ -437,21 +430,14 @@ ggtt_write(struct io_mapping *mapping,
 	   char __user *user_data, int length)
 {
 	void __iomem *vaddr;
-	unsigned long unwritten;
+	bool fail = false;
 
 	/* We can use the cpu mem copy function because this is X86. */
-	vaddr = io_mapping_map_atomic_wc(mapping, base);
-	unwritten = __copy_from_user_inatomic_nocache((void __force *)vaddr + offset,
-						      user_data, length);
-	io_mapping_unmap_atomic(vaddr);
-	if (unwritten) {
-		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
-		unwritten = copy_from_user((void __force *)vaddr + offset,
-					   user_data, length);
-		io_mapping_unmap(vaddr);
-	}
-
-	return unwritten;
+	vaddr = io_mapping_map_local_wc(mapping, base);
+	if (copy_from_user((void __force *)vaddr + offset, user_data, length))
+		fail = true;
+	io_mapping_unmap_local(vaddr);
+	return fail;
 }
 
 /**
--- a/drivers/gpu/drm/i915/selftests/i915_gem.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem.c
@@ -58,12 +58,12 @@ static void trash_stolen(struct drm_i915
 
 		ggtt->vm.insert_page(&ggtt->vm, dma, slot, I915_CACHE_NONE, 0);
 
-		s = io_mapping_map_atomic_wc(&ggtt->iomap, slot);
+		s = io_mapping_map_local_wc(&ggtt->iomap, slot);
 		for (x = 0; x < PAGE_SIZE / sizeof(u32); x++) {
 			prng = next_pseudo_random32(prng);
 			iowrite32(prng, &s[x]);
 		}
-		io_mapping_unmap_atomic(s);
+		io_mapping_unmap_local(s);
 	}
 
 	ggtt->vm.clear_range(&ggtt->vm, slot, PAGE_SIZE);
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -1201,9 +1201,9 @@ static int igt_ggtt_page(void *arg)
 		u64 offset = tmp.start + order[n] * PAGE_SIZE;
 		u32 __iomem *vaddr;
 
-		vaddr = io_mapping_map_atomic_wc(&ggtt->iomap, offset);
+		vaddr = io_mapping_map_local_wc(&ggtt->iomap, offset);
 		iowrite32(n, vaddr + n);
-		io_mapping_unmap_atomic(vaddr);
+		io_mapping_unmap_local(vaddr);
 	}
 	intel_gt_flush_ggtt_writes(ggtt->vm.gt);
 
@@ -1213,9 +1213,9 @@ static int igt_ggtt_page(void *arg)
 		u32 __iomem *vaddr;
 		u32 val;
 
-		vaddr = io_mapping_map_atomic_wc(&ggtt->iomap, offset);
+		vaddr = io_mapping_map_local_wc(&ggtt->iomap, offset);
 		val = ioread32(vaddr + n);
-		io_mapping_unmap_atomic(vaddr);
+		io_mapping_unmap_local(vaddr);
 
 		if (val != n) {
 			pr_err("insert page failed: found %d, expected %d\n",